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1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/pagemap.h>
16 #include <linux/pagevec.h>
17 #include <linux/mpage.h>
18 #include <linux/fs.h>
19 #include <linux/writeback.h>
20 #include <linux/swap.h>
21 #include <linux/gfs2_ondisk.h>
22 #include <linux/backing-dev.h>
23 #include <linux/uio.h>
24 #include <trace/events/writeback.h>
25
26 #include "gfs2.h"
27 #include "incore.h"
28 #include "bmap.h"
29 #include "glock.h"
30 #include "inode.h"
31 #include "log.h"
32 #include "meta_io.h"
33 #include "quota.h"
34 #include "trans.h"
35 #include "rgrp.h"
36 #include "super.h"
37 #include "util.h"
38 #include "glops.h"
39
40
41 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
42 unsigned int from, unsigned int to)
43 {
44 struct buffer_head *head = page_buffers(page);
45 unsigned int bsize = head->b_size;
46 struct buffer_head *bh;
47 unsigned int start, end;
48
49 for (bh = head, start = 0; bh != head || !start;
50 bh = bh->b_this_page, start = end) {
51 end = start + bsize;
52 if (end <= from || start >= to)
53 continue;
54 if (gfs2_is_jdata(ip))
55 set_buffer_uptodate(bh);
56 gfs2_trans_add_data(ip->i_gl, bh);
57 }
58 }
59
60 /**
61 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
62 * @inode: The inode
63 * @lblock: The block number to look up
64 * @bh_result: The buffer head to return the result in
65 * @create: Non-zero if we may add block to the file
66 *
67 * Returns: errno
68 */
69
70 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
71 struct buffer_head *bh_result, int create)
72 {
73 int error;
74
75 error = gfs2_block_map(inode, lblock, bh_result, 0);
76 if (error)
77 return error;
78 if (!buffer_mapped(bh_result))
79 return -EIO;
80 return 0;
81 }
82
83 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
84 struct buffer_head *bh_result, int create)
85 {
86 return gfs2_block_map(inode, lblock, bh_result, 0);
87 }
88
89 /**
90 * gfs2_writepage_common - Common bits of writepage
91 * @page: The page to be written
92 * @wbc: The writeback control
93 *
94 * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
95 */
96
97 static int gfs2_writepage_common(struct page *page,
98 struct writeback_control *wbc)
99 {
100 struct inode *inode = page->mapping->host;
101 struct gfs2_inode *ip = GFS2_I(inode);
102 struct gfs2_sbd *sdp = GFS2_SB(inode);
103 loff_t i_size = i_size_read(inode);
104 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
105 unsigned offset;
106
107 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
108 goto out;
109 if (current->journal_info)
110 goto redirty;
111 /* Is the page fully outside i_size? (truncate in progress) */
112 offset = i_size & (PAGE_CACHE_SIZE-1);
113 if (page->index > end_index || (page->index == end_index && !offset)) {
114 page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
115 goto out;
116 }
117 return 1;
118 redirty:
119 redirty_page_for_writepage(wbc, page);
120 out:
121 unlock_page(page);
122 return 0;
123 }
124
125 /**
126 * gfs2_writepage - Write page for writeback mappings
127 * @page: The page
128 * @wbc: The writeback control
129 *
130 */
131
132 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
133 {
134 int ret;
135
136 ret = gfs2_writepage_common(page, wbc);
137 if (ret <= 0)
138 return ret;
139
140 return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
141 }
142
143 /**
144 * __gfs2_jdata_writepage - The core of jdata writepage
145 * @page: The page to write
146 * @wbc: The writeback control
147 *
148 * This is shared between writepage and writepages and implements the
149 * core of the writepage operation. If a transaction is required then
150 * PageChecked will have been set and the transaction will have
151 * already been started before this is called.
152 */
153
154 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
155 {
156 struct inode *inode = page->mapping->host;
157 struct gfs2_inode *ip = GFS2_I(inode);
158 struct gfs2_sbd *sdp = GFS2_SB(inode);
159
160 if (PageChecked(page)) {
161 ClearPageChecked(page);
162 if (!page_has_buffers(page)) {
163 create_empty_buffers(page, inode->i_sb->s_blocksize,
164 (1 << BH_Dirty)|(1 << BH_Uptodate));
165 }
166 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
167 }
168 return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
169 }
170
171 /**
172 * gfs2_jdata_writepage - Write complete page
173 * @page: Page to write
174 *
175 * Returns: errno
176 *
177 */
178
179 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
180 {
181 struct inode *inode = page->mapping->host;
182 struct gfs2_sbd *sdp = GFS2_SB(inode);
183 int ret;
184 int done_trans = 0;
185
186 if (PageChecked(page)) {
187 if (wbc->sync_mode != WB_SYNC_ALL)
188 goto out_ignore;
189 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
190 if (ret)
191 goto out_ignore;
192 done_trans = 1;
193 }
194 ret = gfs2_writepage_common(page, wbc);
195 if (ret > 0)
196 ret = __gfs2_jdata_writepage(page, wbc);
197 if (done_trans)
198 gfs2_trans_end(sdp);
199 return ret;
200
201 out_ignore:
202 redirty_page_for_writepage(wbc, page);
203 unlock_page(page);
204 return 0;
205 }
206
207 /**
208 * gfs2_writepages - Write a bunch of dirty pages back to disk
209 * @mapping: The mapping to write
210 * @wbc: Write-back control
211 *
212 * Used for both ordered and writeback modes.
213 */
214 static int gfs2_writepages(struct address_space *mapping,
215 struct writeback_control *wbc)
216 {
217 return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
218 }
219
220 /**
221 * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
222 * @mapping: The mapping
223 * @wbc: The writeback control
224 * @writepage: The writepage function to call for each page
225 * @pvec: The vector of pages
226 * @nr_pages: The number of pages to write
227 *
228 * Returns: non-zero if loop should terminate, zero otherwise
229 */
230
231 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
232 struct writeback_control *wbc,
233 struct pagevec *pvec,
234 int nr_pages, pgoff_t end,
235 pgoff_t *done_index)
236 {
237 struct inode *inode = mapping->host;
238 struct gfs2_sbd *sdp = GFS2_SB(inode);
239 unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
240 int i;
241 int ret;
242
243 ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
244 if (ret < 0)
245 return ret;
246
247 for(i = 0; i < nr_pages; i++) {
248 struct page *page = pvec->pages[i];
249
250 /*
251 * At this point, the page may be truncated or
252 * invalidated (changing page->mapping to NULL), or
253 * even swizzled back from swapper_space to tmpfs file
254 * mapping. However, page->index will not change
255 * because we have a reference on the page.
256 */
257 if (page->index > end) {
258 /*
259 * can't be range_cyclic (1st pass) because
260 * end == -1 in that case.
261 */
262 ret = 1;
263 break;
264 }
265
266 *done_index = page->index;
267
268 lock_page(page);
269
270 if (unlikely(page->mapping != mapping)) {
271 continue_unlock:
272 unlock_page(page);
273 continue;
274 }
275
276 if (!PageDirty(page)) {
277 /* someone wrote it for us */
278 goto continue_unlock;
279 }
280
281 if (PageWriteback(page)) {
282 if (wbc->sync_mode != WB_SYNC_NONE)
283 wait_on_page_writeback(page);
284 else
285 goto continue_unlock;
286 }
287
288 BUG_ON(PageWriteback(page));
289 if (!clear_page_dirty_for_io(page))
290 goto continue_unlock;
291
292 trace_wbc_writepage(wbc, inode_to_bdi(inode));
293
294 ret = __gfs2_jdata_writepage(page, wbc);
295 if (unlikely(ret)) {
296 if (ret == AOP_WRITEPAGE_ACTIVATE) {
297 unlock_page(page);
298 ret = 0;
299 } else {
300
301 /*
302 * done_index is set past this page,
303 * so media errors will not choke
304 * background writeout for the entire
305 * file. This has consequences for
306 * range_cyclic semantics (ie. it may
307 * not be suitable for data integrity
308 * writeout).
309 */
310 *done_index = page->index + 1;
311 ret = 1;
312 break;
313 }
314 }
315
316 /*
317 * We stop writing back only if we are not doing
318 * integrity sync. In case of integrity sync we have to
319 * keep going until we have written all the pages
320 * we tagged for writeback prior to entering this loop.
321 */
322 if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
323 ret = 1;
324 break;
325 }
326
327 }
328 gfs2_trans_end(sdp);
329 return ret;
330 }
331
332 /**
333 * gfs2_write_cache_jdata - Like write_cache_pages but different
334 * @mapping: The mapping to write
335 * @wbc: The writeback control
336 * @writepage: The writepage function to call
337 * @data: The data to pass to writepage
338 *
339 * The reason that we use our own function here is that we need to
340 * start transactions before we grab page locks. This allows us
341 * to get the ordering right.
342 */
343
344 static int gfs2_write_cache_jdata(struct address_space *mapping,
345 struct writeback_control *wbc)
346 {
347 int ret = 0;
348 int done = 0;
349 struct pagevec pvec;
350 int nr_pages;
351 pgoff_t uninitialized_var(writeback_index);
352 pgoff_t index;
353 pgoff_t end;
354 pgoff_t done_index;
355 int cycled;
356 int range_whole = 0;
357 int tag;
358
359 pagevec_init(&pvec, 0);
360 if (wbc->range_cyclic) {
361 writeback_index = mapping->writeback_index; /* prev offset */
362 index = writeback_index;
363 if (index == 0)
364 cycled = 1;
365 else
366 cycled = 0;
367 end = -1;
368 } else {
369 index = wbc->range_start >> PAGE_CACHE_SHIFT;
370 end = wbc->range_end >> PAGE_CACHE_SHIFT;
371 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
372 range_whole = 1;
373 cycled = 1; /* ignore range_cyclic tests */
374 }
375 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
376 tag = PAGECACHE_TAG_TOWRITE;
377 else
378 tag = PAGECACHE_TAG_DIRTY;
379
380 retry:
381 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
382 tag_pages_for_writeback(mapping, index, end);
383 done_index = index;
384 while (!done && (index <= end)) {
385 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
386 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
387 if (nr_pages == 0)
388 break;
389
390 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end, &done_index);
391 if (ret)
392 done = 1;
393 if (ret > 0)
394 ret = 0;
395 pagevec_release(&pvec);
396 cond_resched();
397 }
398
399 if (!cycled && !done) {
400 /*
401 * range_cyclic:
402 * We hit the last page and there is more work to be done: wrap
403 * back to the start of the file
404 */
405 cycled = 1;
406 index = 0;
407 end = writeback_index - 1;
408 goto retry;
409 }
410
411 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
412 mapping->writeback_index = done_index;
413
414 return ret;
415 }
416
417
418 /**
419 * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
420 * @mapping: The mapping to write
421 * @wbc: The writeback control
422 *
423 */
424
425 static int gfs2_jdata_writepages(struct address_space *mapping,
426 struct writeback_control *wbc)
427 {
428 struct gfs2_inode *ip = GFS2_I(mapping->host);
429 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
430 int ret;
431
432 ret = gfs2_write_cache_jdata(mapping, wbc);
433 if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
434 gfs2_log_flush(sdp, ip->i_gl, NORMAL_FLUSH);
435 ret = gfs2_write_cache_jdata(mapping, wbc);
436 }
437 return ret;
438 }
439
440 /**
441 * stuffed_readpage - Fill in a Linux page with stuffed file data
442 * @ip: the inode
443 * @page: the page
444 *
445 * Returns: errno
446 */
447
448 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
449 {
450 struct buffer_head *dibh;
451 u64 dsize = i_size_read(&ip->i_inode);
452 void *kaddr;
453 int error;
454
455 /*
456 * Due to the order of unstuffing files and ->fault(), we can be
457 * asked for a zero page in the case of a stuffed file being extended,
458 * so we need to supply one here. It doesn't happen often.
459 */
460 if (unlikely(page->index)) {
461 zero_user(page, 0, PAGE_CACHE_SIZE);
462 SetPageUptodate(page);
463 return 0;
464 }
465
466 error = gfs2_meta_inode_buffer(ip, &dibh);
467 if (error)
468 return error;
469
470 kaddr = kmap_atomic(page);
471 if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
472 dsize = (dibh->b_size - sizeof(struct gfs2_dinode));
473 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
474 memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
475 kunmap_atomic(kaddr);
476 flush_dcache_page(page);
477 brelse(dibh);
478 SetPageUptodate(page);
479
480 return 0;
481 }
482
483
484 /**
485 * __gfs2_readpage - readpage
486 * @file: The file to read a page for
487 * @page: The page to read
488 *
489 * This is the core of gfs2's readpage. Its used by the internal file
490 * reading code as in that case we already hold the glock. Also its
491 * called by gfs2_readpage() once the required lock has been granted.
492 *
493 */
494
495 static int __gfs2_readpage(void *file, struct page *page)
496 {
497 struct gfs2_inode *ip = GFS2_I(page->mapping->host);
498 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
499 int error;
500
501 if (gfs2_is_stuffed(ip)) {
502 error = stuffed_readpage(ip, page);
503 unlock_page(page);
504 } else {
505 error = mpage_readpage(page, gfs2_block_map);
506 }
507
508 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
509 return -EIO;
510
511 return error;
512 }
513
514 /**
515 * gfs2_readpage - read a page of a file
516 * @file: The file to read
517 * @page: The page of the file
518 *
519 * This deals with the locking required. We have to unlock and
520 * relock the page in order to get the locking in the right
521 * order.
522 */
523
524 static int gfs2_readpage(struct file *file, struct page *page)
525 {
526 struct address_space *mapping = page->mapping;
527 struct gfs2_inode *ip = GFS2_I(mapping->host);
528 struct gfs2_holder gh;
529 int error;
530
531 unlock_page(page);
532 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
533 error = gfs2_glock_nq(&gh);
534 if (unlikely(error))
535 goto out;
536 error = AOP_TRUNCATED_PAGE;
537 lock_page(page);
538 if (page->mapping == mapping && !PageUptodate(page))
539 error = __gfs2_readpage(file, page);
540 else
541 unlock_page(page);
542 gfs2_glock_dq(&gh);
543 out:
544 gfs2_holder_uninit(&gh);
545 if (error && error != AOP_TRUNCATED_PAGE)
546 lock_page(page);
547 return error;
548 }
549
550 /**
551 * gfs2_internal_read - read an internal file
552 * @ip: The gfs2 inode
553 * @buf: The buffer to fill
554 * @pos: The file position
555 * @size: The amount to read
556 *
557 */
558
559 int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
560 unsigned size)
561 {
562 struct address_space *mapping = ip->i_inode.i_mapping;
563 unsigned long index = *pos / PAGE_CACHE_SIZE;
564 unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
565 unsigned copied = 0;
566 unsigned amt;
567 struct page *page;
568 void *p;
569
570 do {
571 amt = size - copied;
572 if (offset + size > PAGE_CACHE_SIZE)
573 amt = PAGE_CACHE_SIZE - offset;
574 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
575 if (IS_ERR(page))
576 return PTR_ERR(page);
577 p = kmap_atomic(page);
578 memcpy(buf + copied, p + offset, amt);
579 kunmap_atomic(p);
580 page_cache_release(page);
581 copied += amt;
582 index++;
583 offset = 0;
584 } while(copied < size);
585 (*pos) += size;
586 return size;
587 }
588
589 /**
590 * gfs2_readpages - Read a bunch of pages at once
591 *
592 * Some notes:
593 * 1. This is only for readahead, so we can simply ignore any things
594 * which are slightly inconvenient (such as locking conflicts between
595 * the page lock and the glock) and return having done no I/O. Its
596 * obviously not something we'd want to do on too regular a basis.
597 * Any I/O we ignore at this time will be done via readpage later.
598 * 2. We don't handle stuffed files here we let readpage do the honours.
599 * 3. mpage_readpages() does most of the heavy lifting in the common case.
600 * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
601 */
602
603 static int gfs2_readpages(struct file *file, struct address_space *mapping,
604 struct list_head *pages, unsigned nr_pages)
605 {
606 struct inode *inode = mapping->host;
607 struct gfs2_inode *ip = GFS2_I(inode);
608 struct gfs2_sbd *sdp = GFS2_SB(inode);
609 struct gfs2_holder gh;
610 int ret;
611
612 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
613 ret = gfs2_glock_nq(&gh);
614 if (unlikely(ret))
615 goto out_uninit;
616 if (!gfs2_is_stuffed(ip))
617 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
618 gfs2_glock_dq(&gh);
619 out_uninit:
620 gfs2_holder_uninit(&gh);
621 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
622 ret = -EIO;
623 return ret;
624 }
625
626 /**
627 * gfs2_write_begin - Begin to write to a file
628 * @file: The file to write to
629 * @mapping: The mapping in which to write
630 * @pos: The file offset at which to start writing
631 * @len: Length of the write
632 * @flags: Various flags
633 * @pagep: Pointer to return the page
634 * @fsdata: Pointer to return fs data (unused by GFS2)
635 *
636 * Returns: errno
637 */
638
639 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
640 loff_t pos, unsigned len, unsigned flags,
641 struct page **pagep, void **fsdata)
642 {
643 struct gfs2_inode *ip = GFS2_I(mapping->host);
644 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
645 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
646 unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
647 unsigned requested = 0;
648 int alloc_required;
649 int error = 0;
650 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
651 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
652 struct page *page;
653
654 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
655 error = gfs2_glock_nq(&ip->i_gh);
656 if (unlikely(error))
657 goto out_uninit;
658 if (&ip->i_inode == sdp->sd_rindex) {
659 error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
660 GL_NOCACHE, &m_ip->i_gh);
661 if (unlikely(error)) {
662 gfs2_glock_dq(&ip->i_gh);
663 goto out_uninit;
664 }
665 }
666
667 alloc_required = gfs2_write_alloc_required(ip, pos, len);
668
669 if (alloc_required || gfs2_is_jdata(ip))
670 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
671
672 if (alloc_required) {
673 struct gfs2_alloc_parms ap = { .aflags = 0, };
674 error = gfs2_quota_lock_check(ip);
675 if (error)
676 goto out_unlock;
677
678 requested = data_blocks + ind_blocks;
679 ap.target = requested;
680 error = gfs2_inplace_reserve(ip, &ap);
681 if (error)
682 goto out_qunlock;
683 }
684
685 rblocks = RES_DINODE + ind_blocks;
686 if (gfs2_is_jdata(ip))
687 rblocks += data_blocks ? data_blocks : 1;
688 if (ind_blocks || data_blocks)
689 rblocks += RES_STATFS + RES_QUOTA;
690 if (&ip->i_inode == sdp->sd_rindex)
691 rblocks += 2 * RES_STATFS;
692 if (alloc_required)
693 rblocks += gfs2_rg_blocks(ip, requested);
694
695 error = gfs2_trans_begin(sdp, rblocks,
696 PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
697 if (error)
698 goto out_trans_fail;
699
700 error = -ENOMEM;
701 flags |= AOP_FLAG_NOFS;
702 page = grab_cache_page_write_begin(mapping, index, flags);
703 *pagep = page;
704 if (unlikely(!page))
705 goto out_endtrans;
706
707 if (gfs2_is_stuffed(ip)) {
708 error = 0;
709 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
710 error = gfs2_unstuff_dinode(ip, page);
711 if (error == 0)
712 goto prepare_write;
713 } else if (!PageUptodate(page)) {
714 error = stuffed_readpage(ip, page);
715 }
716 goto out;
717 }
718
719 prepare_write:
720 error = __block_write_begin(page, from, len, gfs2_block_map);
721 out:
722 if (error == 0)
723 return 0;
724
725 unlock_page(page);
726 page_cache_release(page);
727
728 gfs2_trans_end(sdp);
729 if (pos + len > ip->i_inode.i_size)
730 gfs2_trim_blocks(&ip->i_inode);
731 goto out_trans_fail;
732
733 out_endtrans:
734 gfs2_trans_end(sdp);
735 out_trans_fail:
736 if (alloc_required) {
737 gfs2_inplace_release(ip);
738 out_qunlock:
739 gfs2_quota_unlock(ip);
740 }
741 out_unlock:
742 if (&ip->i_inode == sdp->sd_rindex) {
743 gfs2_glock_dq(&m_ip->i_gh);
744 gfs2_holder_uninit(&m_ip->i_gh);
745 }
746 gfs2_glock_dq(&ip->i_gh);
747 out_uninit:
748 gfs2_holder_uninit(&ip->i_gh);
749 return error;
750 }
751
752 /**
753 * adjust_fs_space - Adjusts the free space available due to gfs2_grow
754 * @inode: the rindex inode
755 */
756 static void adjust_fs_space(struct inode *inode)
757 {
758 struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
759 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
760 struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
761 struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
762 struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
763 struct buffer_head *m_bh, *l_bh;
764 u64 fs_total, new_free;
765
766 /* Total up the file system space, according to the latest rindex. */
767 fs_total = gfs2_ri_total(sdp);
768 if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
769 return;
770
771 spin_lock(&sdp->sd_statfs_spin);
772 gfs2_statfs_change_in(m_sc, m_bh->b_data +
773 sizeof(struct gfs2_dinode));
774 if (fs_total > (m_sc->sc_total + l_sc->sc_total))
775 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
776 else
777 new_free = 0;
778 spin_unlock(&sdp->sd_statfs_spin);
779 fs_warn(sdp, "File system extended by %llu blocks.\n",
780 (unsigned long long)new_free);
781 gfs2_statfs_change(sdp, new_free, new_free, 0);
782
783 if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
784 goto out;
785 update_statfs(sdp, m_bh, l_bh);
786 brelse(l_bh);
787 out:
788 brelse(m_bh);
789 }
790
791 /**
792 * gfs2_stuffed_write_end - Write end for stuffed files
793 * @inode: The inode
794 * @dibh: The buffer_head containing the on-disk inode
795 * @pos: The file position
796 * @len: The length of the write
797 * @copied: How much was actually copied by the VFS
798 * @page: The page
799 *
800 * This copies the data from the page into the inode block after
801 * the inode data structure itself.
802 *
803 * Returns: errno
804 */
805 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
806 loff_t pos, unsigned len, unsigned copied,
807 struct page *page)
808 {
809 struct gfs2_inode *ip = GFS2_I(inode);
810 struct gfs2_sbd *sdp = GFS2_SB(inode);
811 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
812 u64 to = pos + copied;
813 void *kaddr;
814 unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
815
816 BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
817 kaddr = kmap_atomic(page);
818 memcpy(buf + pos, kaddr + pos, copied);
819 memset(kaddr + pos + copied, 0, len - copied);
820 flush_dcache_page(page);
821 kunmap_atomic(kaddr);
822
823 if (!PageUptodate(page))
824 SetPageUptodate(page);
825 unlock_page(page);
826 page_cache_release(page);
827
828 if (copied) {
829 if (inode->i_size < to)
830 i_size_write(inode, to);
831 mark_inode_dirty(inode);
832 }
833
834 if (inode == sdp->sd_rindex) {
835 adjust_fs_space(inode);
836 sdp->sd_rindex_uptodate = 0;
837 }
838
839 brelse(dibh);
840 gfs2_trans_end(sdp);
841 if (inode == sdp->sd_rindex) {
842 gfs2_glock_dq(&m_ip->i_gh);
843 gfs2_holder_uninit(&m_ip->i_gh);
844 }
845 gfs2_glock_dq(&ip->i_gh);
846 gfs2_holder_uninit(&ip->i_gh);
847 return copied;
848 }
849
850 /**
851 * gfs2_write_end
852 * @file: The file to write to
853 * @mapping: The address space to write to
854 * @pos: The file position
855 * @len: The length of the data
856 * @copied:
857 * @page: The page that has been written
858 * @fsdata: The fsdata (unused in GFS2)
859 *
860 * The main write_end function for GFS2. We have a separate one for
861 * stuffed files as they are slightly different, otherwise we just
862 * put our locking around the VFS provided functions.
863 *
864 * Returns: errno
865 */
866
867 static int gfs2_write_end(struct file *file, struct address_space *mapping,
868 loff_t pos, unsigned len, unsigned copied,
869 struct page *page, void *fsdata)
870 {
871 struct inode *inode = page->mapping->host;
872 struct gfs2_inode *ip = GFS2_I(inode);
873 struct gfs2_sbd *sdp = GFS2_SB(inode);
874 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
875 struct buffer_head *dibh;
876 unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
877 unsigned int to = from + len;
878 int ret;
879 struct gfs2_trans *tr = current->journal_info;
880 BUG_ON(!tr);
881
882 BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
883
884 ret = gfs2_meta_inode_buffer(ip, &dibh);
885 if (unlikely(ret)) {
886 unlock_page(page);
887 page_cache_release(page);
888 goto failed;
889 }
890
891 if (gfs2_is_stuffed(ip))
892 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
893
894 if (!gfs2_is_writeback(ip))
895 gfs2_page_add_databufs(ip, page, from, to);
896
897 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
898 if (tr->tr_num_buf_new)
899 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
900 else
901 gfs2_trans_add_meta(ip->i_gl, dibh);
902
903
904 if (inode == sdp->sd_rindex) {
905 adjust_fs_space(inode);
906 sdp->sd_rindex_uptodate = 0;
907 }
908
909 brelse(dibh);
910 failed:
911 gfs2_trans_end(sdp);
912 gfs2_inplace_release(ip);
913 if (ip->i_res->rs_qa_qd_num)
914 gfs2_quota_unlock(ip);
915 if (inode == sdp->sd_rindex) {
916 gfs2_glock_dq(&m_ip->i_gh);
917 gfs2_holder_uninit(&m_ip->i_gh);
918 }
919 gfs2_glock_dq(&ip->i_gh);
920 gfs2_holder_uninit(&ip->i_gh);
921 return ret;
922 }
923
924 /**
925 * gfs2_set_page_dirty - Page dirtying function
926 * @page: The page to dirty
927 *
928 * Returns: 1 if it dirtyed the page, or 0 otherwise
929 */
930
931 static int gfs2_set_page_dirty(struct page *page)
932 {
933 SetPageChecked(page);
934 return __set_page_dirty_buffers(page);
935 }
936
937 /**
938 * gfs2_bmap - Block map function
939 * @mapping: Address space info
940 * @lblock: The block to map
941 *
942 * Returns: The disk address for the block or 0 on hole or error
943 */
944
945 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
946 {
947 struct gfs2_inode *ip = GFS2_I(mapping->host);
948 struct gfs2_holder i_gh;
949 sector_t dblock = 0;
950 int error;
951
952 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
953 if (error)
954 return 0;
955
956 if (!gfs2_is_stuffed(ip))
957 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
958
959 gfs2_glock_dq_uninit(&i_gh);
960
961 return dblock;
962 }
963
964 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
965 {
966 struct gfs2_bufdata *bd;
967
968 lock_buffer(bh);
969 gfs2_log_lock(sdp);
970 clear_buffer_dirty(bh);
971 bd = bh->b_private;
972 if (bd) {
973 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
974 list_del_init(&bd->bd_list);
975 else
976 gfs2_remove_from_journal(bh, current->journal_info, 0);
977 }
978 bh->b_bdev = NULL;
979 clear_buffer_mapped(bh);
980 clear_buffer_req(bh);
981 clear_buffer_new(bh);
982 gfs2_log_unlock(sdp);
983 unlock_buffer(bh);
984 }
985
986 static void gfs2_invalidatepage(struct page *page, unsigned int offset,
987 unsigned int length)
988 {
989 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
990 unsigned int stop = offset + length;
991 int partial_page = (offset || length < PAGE_CACHE_SIZE);
992 struct buffer_head *bh, *head;
993 unsigned long pos = 0;
994
995 BUG_ON(!PageLocked(page));
996 if (!partial_page)
997 ClearPageChecked(page);
998 if (!page_has_buffers(page))
999 goto out;
1000
1001 bh = head = page_buffers(page);
1002 do {
1003 if (pos + bh->b_size > stop)
1004 return;
1005
1006 if (offset <= pos)
1007 gfs2_discard(sdp, bh);
1008 pos += bh->b_size;
1009 bh = bh->b_this_page;
1010 } while (bh != head);
1011 out:
1012 if (!partial_page)
1013 try_to_release_page(page, 0);
1014 }
1015
1016 /**
1017 * gfs2_ok_for_dio - check that dio is valid on this file
1018 * @ip: The inode
1019 * @rw: READ or WRITE
1020 * @offset: The offset at which we are reading or writing
1021 *
1022 * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
1023 * 1 (to accept the i/o request)
1024 */
1025 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
1026 {
1027 /*
1028 * Should we return an error here? I can't see that O_DIRECT for
1029 * a stuffed file makes any sense. For now we'll silently fall
1030 * back to buffered I/O
1031 */
1032 if (gfs2_is_stuffed(ip))
1033 return 0;
1034
1035 if (offset >= i_size_read(&ip->i_inode))
1036 return 0;
1037 return 1;
1038 }
1039
1040
1041
1042 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
1043 struct iov_iter *iter, loff_t offset)
1044 {
1045 struct file *file = iocb->ki_filp;
1046 struct inode *inode = file->f_mapping->host;
1047 struct address_space *mapping = inode->i_mapping;
1048 struct gfs2_inode *ip = GFS2_I(inode);
1049 struct gfs2_holder gh;
1050 int rv;
1051
1052 /*
1053 * Deferred lock, even if its a write, since we do no allocation
1054 * on this path. All we need change is atime, and this lock mode
1055 * ensures that other nodes have flushed their buffered read caches
1056 * (i.e. their page cache entries for this inode). We do not,
1057 * unfortunately have the option of only flushing a range like
1058 * the VFS does.
1059 */
1060 gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
1061 rv = gfs2_glock_nq(&gh);
1062 if (rv)
1063 return rv;
1064 rv = gfs2_ok_for_dio(ip, rw, offset);
1065 if (rv != 1)
1066 goto out; /* dio not valid, fall back to buffered i/o */
1067
1068 /*
1069 * Now since we are holding a deferred (CW) lock at this point, you
1070 * might be wondering why this is ever needed. There is a case however
1071 * where we've granted a deferred local lock against a cached exclusive
1072 * glock. That is ok provided all granted local locks are deferred, but
1073 * it also means that it is possible to encounter pages which are
1074 * cached and possibly also mapped. So here we check for that and sort
1075 * them out ahead of the dio. The glock state machine will take care of
1076 * everything else.
1077 *
1078 * If in fact the cached glock state (gl->gl_state) is deferred (CW) in
1079 * the first place, mapping->nr_pages will always be zero.
1080 */
1081 if (mapping->nrpages) {
1082 loff_t lstart = offset & (PAGE_CACHE_SIZE - 1);
1083 loff_t len = iov_iter_count(iter);
1084 loff_t end = PAGE_ALIGN(offset + len) - 1;
1085
1086 rv = 0;
1087 if (len == 0)
1088 goto out;
1089 if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
1090 unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
1091 rv = filemap_write_and_wait_range(mapping, lstart, end);
1092 if (rv)
1093 goto out;
1094 if (rw == WRITE)
1095 truncate_inode_pages_range(mapping, lstart, end);
1096 }
1097
1098 rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
1099 offset, gfs2_get_block_direct, NULL, NULL, 0);
1100 out:
1101 gfs2_glock_dq(&gh);
1102 gfs2_holder_uninit(&gh);
1103 return rv;
1104 }
1105
1106 /**
1107 * gfs2_releasepage - free the metadata associated with a page
1108 * @page: the page that's being released
1109 * @gfp_mask: passed from Linux VFS, ignored by us
1110 *
1111 * Call try_to_free_buffers() if the buffers in this page can be
1112 * released.
1113 *
1114 * Returns: 0
1115 */
1116
1117 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1118 {
1119 struct address_space *mapping = page->mapping;
1120 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
1121 struct buffer_head *bh, *head;
1122 struct gfs2_bufdata *bd;
1123
1124 if (!page_has_buffers(page))
1125 return 0;
1126
1127 gfs2_log_lock(sdp);
1128 spin_lock(&sdp->sd_ail_lock);
1129 head = bh = page_buffers(page);
1130 do {
1131 if (atomic_read(&bh->b_count))
1132 goto cannot_release;
1133 bd = bh->b_private;
1134 if (bd && bd->bd_tr)
1135 goto cannot_release;
1136 if (buffer_pinned(bh) || buffer_dirty(bh))
1137 goto not_possible;
1138 bh = bh->b_this_page;
1139 } while(bh != head);
1140 spin_unlock(&sdp->sd_ail_lock);
1141
1142 head = bh = page_buffers(page);
1143 do {
1144 bd = bh->b_private;
1145 if (bd) {
1146 gfs2_assert_warn(sdp, bd->bd_bh == bh);
1147 if (!list_empty(&bd->bd_list))
1148 list_del_init(&bd->bd_list);
1149 bd->bd_bh = NULL;
1150 bh->b_private = NULL;
1151 kmem_cache_free(gfs2_bufdata_cachep, bd);
1152 }
1153
1154 bh = bh->b_this_page;
1155 } while (bh != head);
1156 gfs2_log_unlock(sdp);
1157
1158 return try_to_free_buffers(page);
1159
1160 not_possible: /* Should never happen */
1161 WARN_ON(buffer_dirty(bh));
1162 WARN_ON(buffer_pinned(bh));
1163 cannot_release:
1164 spin_unlock(&sdp->sd_ail_lock);
1165 gfs2_log_unlock(sdp);
1166 return 0;
1167 }
1168
1169 static const struct address_space_operations gfs2_writeback_aops = {
1170 .writepage = gfs2_writepage,
1171 .writepages = gfs2_writepages,
1172 .readpage = gfs2_readpage,
1173 .readpages = gfs2_readpages,
1174 .write_begin = gfs2_write_begin,
1175 .write_end = gfs2_write_end,
1176 .bmap = gfs2_bmap,
1177 .invalidatepage = gfs2_invalidatepage,
1178 .releasepage = gfs2_releasepage,
1179 .direct_IO = gfs2_direct_IO,
1180 .migratepage = buffer_migrate_page,
1181 .is_partially_uptodate = block_is_partially_uptodate,
1182 .error_remove_page = generic_error_remove_page,
1183 };
1184
1185 static const struct address_space_operations gfs2_ordered_aops = {
1186 .writepage = gfs2_writepage,
1187 .writepages = gfs2_writepages,
1188 .readpage = gfs2_readpage,
1189 .readpages = gfs2_readpages,
1190 .write_begin = gfs2_write_begin,
1191 .write_end = gfs2_write_end,
1192 .set_page_dirty = gfs2_set_page_dirty,
1193 .bmap = gfs2_bmap,
1194 .invalidatepage = gfs2_invalidatepage,
1195 .releasepage = gfs2_releasepage,
1196 .direct_IO = gfs2_direct_IO,
1197 .migratepage = buffer_migrate_page,
1198 .is_partially_uptodate = block_is_partially_uptodate,
1199 .error_remove_page = generic_error_remove_page,
1200 };
1201
1202 static const struct address_space_operations gfs2_jdata_aops = {
1203 .writepage = gfs2_jdata_writepage,
1204 .writepages = gfs2_jdata_writepages,
1205 .readpage = gfs2_readpage,
1206 .readpages = gfs2_readpages,
1207 .write_begin = gfs2_write_begin,
1208 .write_end = gfs2_write_end,
1209 .set_page_dirty = gfs2_set_page_dirty,
1210 .bmap = gfs2_bmap,
1211 .invalidatepage = gfs2_invalidatepage,
1212 .releasepage = gfs2_releasepage,
1213 .is_partially_uptodate = block_is_partially_uptodate,
1214 .error_remove_page = generic_error_remove_page,
1215 };
1216
1217 void gfs2_set_aops(struct inode *inode)
1218 {
1219 struct gfs2_inode *ip = GFS2_I(inode);
1220
1221 if (gfs2_is_writeback(ip))
1222 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1223 else if (gfs2_is_ordered(ip))
1224 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1225 else if (gfs2_is_jdata(ip))
1226 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1227 else
1228 BUG();
1229 }
1230